I don't understand whether this means vary's over a short amount of time, ie day to day or whether they mean over larger periods of time e.g. have you ever recovered and returned to work? Where do I start with this one at a F2F (tomorrow!)
PIP considers the issues that you have for the "majority of days", however, this does not mean that you only have to consider your condition as it affects you to a particular degree.
As an example; if you were unable to complete an activity on two days a week, could not reliably complete it on two other days a week and would not have problems on the remaining three then you would still meet the requirement as you are unable complete four days a week (2 + 2).
During the day is more difficult and depends on the activity, so again as an example; if due to severe pain in the morning you were unable to dress then you should expect to score points for this even if you could dress later in the day after taking pain medication. However, using the same example for preparing a meal, I would not expect you to score points as the DWP will argue that you could reasonably do this after your medication has taken effect.
Have a look at the Scoring points when your condition varies section in the PIP Claim guide.
There is also a section at the back of the guide that covers the assessment and the questions you are likely to be asked.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems